RobertUI 

As an experiment, I purchased the 'CNC Rear Derailleur 10 Speed Direct Mount/Hanger Mount for Shimano/sram' (https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1) to use with my well-loved wheelset outfitted with an SRAM 11-36 Cassette (PG 1070). The wheelset was running fine on one of my other bikes, so I thought I would try this out with the ridiculously cheap shifter/derailleur setup. The derailleur set screw adjustment allowed me to dial in the big cog with no problem, but with the set screw backed off completely, the chain will not make it to the smallest (11) cog. Looking at the back of the bike, it's obvious that the derailleur only allows me to get to the 2nd highest cog (again, the set screw is backed off completely). Is there a spacer that I could use when mounting the derailleur (the thought being that it would push it away from the hanger)? I've checked alignment with my alignment tools, and the hanger does not appear to be bent. The bike is a Fuji Fuji Crosstown and was previously set up as a 1x7.

I can try to take pictures, but I'm wondering if this is what I get for going with such a cheap derailleur (in which case I will be returning it). Thanks in advance to all of my fellow BF-Bike Mechanics

Troul 

Is the cable tight or slack when set to the smallest cog? you've tried the B screw adjustment? How about the H & L screw?

RobertUI 

I always do my initial adjustments without the cable attached, so in this case, there's no cable (slack). I tried the B screw adjustment (only adjusts the angle) as well as the H&L (H in this case). The issue is mechanical, the derailleur doesn't come "out" or "away" far enough to hit that highest cog. I'll grab a picture when I get off work to show what I'm talking about.

trailangel

Never heard of CNC brand before. I'd pack it back up and return for a refund.

Troul 

Would this be something you'd think could work?
https://www.performancebike.com/whee...n-ds-1/p324953

WM DROP OUT SAVER - THICK DROPOUTS (6.5MM INSERTION)

RobertUI 

I don't think that will help, but thanks I wasn't aware those existed (and I've encountered a few frames with stripped mounts). I believe that a 2mm washer will do what I need (and I'm sure I can scrounge one up) but didn't know if anyone else has ever encountered this. I will probably wind up returning and going with something 'better' but I'm otherwise really impressed with the quality of such a cheap shifter/der combo. This is for my daughter's campus bike, so I'm trying to keep the budget as low as possible while still giving her some better gearing options.

Iride01 

You do know that SRAM and Shimano have DR's that are in the 24 to 30 dollar range too don't you? Why not get something that matches components already on your bike instead of experimenting.


And how many speeds is your rear? The cnc dr on amazon I looked at was only for 10 speed rears.

woodcraft

I think that is a relatively common bike shop hack- add a washer between the wheel and the dropout to move the RD out further, to remedy hesitant shifting to the smallest cog.

squirtdad

it could simply be beyond the derailler range.....but hard to tell as nothing is listed for max rear cog/minimum rear cog, chain wrap and max front ring diference.

get a shimano

cbrstar

The derailleur clearly says it's for a 10 speed, and you are using a 11 speed cassette. And you are confused to why it won't shift down to the 11th speed? Am I missing something here?

Litespud

could you put a washer or spacer between the RD bolt and the hanger to physically move the RD outboard a bit? You'd have to redo the H/L limits. There's likely more than enough thread on the RD bolt to accommodate a spacer.

Iride01 

I feel as if I'm in the same boat too. But the OP did say they were "experimenting" in their OP.

How much more money experimenting do they want to spend before paying less for the correct part? Maybe it's more a matter of proving they can do it.

dsbrantjr

"ShenZhenShiShiLiLanTianKeJiYouXianGongSi" ( really, copied from Amazon listing) certainly sounds like a well-established, reputable firm.

Troul 

That's just how you annunciate "shimano"

elocution of shimano : Shen-ZhenShiShiLiLa-nTi-a-(nKeJiYou)XianGongSi/

pdlamb

Since 4:00 Tuesday morning!

Camilo

Is there a spacer behind the cassette that you could remove?

RobertUI 

I had a typo in the cassette model number, sorry about that it's definitely a 10 speed cassette that I'm using.

Sadly no, but I think I may have remedied the situation, I checked back after work, and there was a slight bend to the hanger. I straightened it out, and the derailleur (with the set screw backed all the way out) just makes it there. I am still planning to put a washer there to give me a little more room.

This ^ I think I may have done this at the shop I worked at in college (30 years ago) though we were always trying things that might save a few pennies.

prj71

^^^This. Buy a SRAM or Shimano.

RobertUI 

This experiment was intended to test the quality of the cheap chinese stuff and compare it to the brand name... my thought is that if it worked 'well enough' it might be good for a campus commuter that's likely to get stolen at some point in its life (college campus).

Iride01 

But that cheap stuff cost the same as a 10 speed Shimano DR. And I think SRAM has them that inexpensive too. Maybe not on Amazon, but many other online retailers of bike components sell 10 speed Shimano for the same price as what your DR was on Amazon.

trailangel

10 sp SIS or 10 sp SYS..... doesn't say.

prj71

So how did that work out for you?

Troul 

the no name brand is a good theft deterrent. Anyone that knows bicycle parts will know that particular der is low buck Chinesium.

Kapusta

For all the trashing of this no name stuff, it turned out to be a hangar issues.

FWIW, I had to shim a SRAM X9 rd one time to get it to reach the lowest cog.